Apparatus for superheating steam.



E. E. OSBORNE.

APPARATUS FOR SUPERHEATING STEAM.

APPLICATION IILED APR. 18, 1904. RENEWED DBO. 6, 1909. NJY'A Patented 0011.4, 1910.

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E. F. OSBORNE.

APPARATUS FOR SUPERHEATING STEAM.

APPLICATION mum APR. 18, 1904. RENEWED mac. 6, 1909.

Patented Oct 1, 1910.

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an snares smear EUGENE F. OSBORNE, OF CHICAGO, ILLINOIS, ASSIGNOR TO OSBORNE STEAM ENGI- NEERING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

APPARATUS FOR SUPERHEATING STEAM.

Application filed April 18, 1904, Serial No. 203,769.

To all whom it may concern."

Be it known that I, EUGENE F. OsBoRNn, a citizen of the United States, of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Apparatus for Superheating Steam; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in apparatus for superheating steam and to the combination of such an apparatus with a steam power producing plant, and the invention consists in the matters hereinafter set forth and more particularly pointed out in the appended claims.

Among the ObjQCtS of my invention is to produce a steam superheating apparatus of practical construction and economic operation in which steam may be superheated to a suitably high temperature without subjecting the apparatus to dangerous pressure such as is liable to result in explosion thereof.

A further object of the invention is to provide means for regulating the operation of the apparatus whereby the temperature of the superheating agent may be controlled to accord with a selected temperature of the superheated steam and whereby also the temperature of the superheating agent is prevented from rising beyond an objectionable point upon the temporary discontinuance of the use of the superheated steam.

The superheater herein disclosed is of that class illustrated in my prior U. S. Letters Patent No. 762,248, granted June 7th, 1904:, wherein the heat to superheat the steam is transmitted to the steam through the medium of a liquid (preferably having a higher boiling point than water) as distin guished from what may be termed dry super-heaters, wherein the steam is superheated by the direct action of flames playing about the pipes through which the steam passes.

I have shown in the drawings, one form of apparatus embodying my invention, though it is obvious from the description which follows that the structural details thereof may be widely varied without departing from the spirit of the invention.

In the drawings :Figure 1 is a view, principally diagrammatic in its nature, of a Specification of Letters Patent.

Patented Oct. 4, 1910.

Renewed December 6, 1909. Serial No. 531,693.

steam generator, a steam engine and my improved superheating apparatus for superheating the steam during its passage from the generator to the engine. Fig. 2 is an enlarged sectional view of the superheating apparatus. Fig. 3 is a fragmentary front elevation of the draft and check-draft doors of the furnace of the super-heater. Fig. a is a side elevation of the part shown in Fig. 3.

As shown in the drawings, A designates a steam generator and B an engine receiving steam therefrom.

C (Fig. l) designates, as a whole, my improved superheating apparatus. Said apparatus comprises a furnace G provided with a draft-door c and a check-draft door 0 I) designates a heat transmitter comprising, as herein shown, a cylindric casing D having end walls (Z (Z and a plurality of longitudinal tubes D extending between and opening through diaphragms or heads (Z d in the casing whereby are formed chambers cl" d at the ends of the casing which communicate with each other through said tubes D Steam from the generator A is directed through said tubes and is therein subjected to the influence of a superheating agent which is passed through the casing, the easing constituting part of a closed circuit through which a superhcating agent is continuously passed. Said closed circuit enibraces a plurality of tubes D located within the furnace C which communicates with one end of the casing through a pipe or passage D and at their other ends through a pipe D The closed circuit thus includes the casing D between the heads (Z (Z the tubes D and connecting pipes D D and the superheating agent is heated by the fire within the furnace while passing through the tubes D and transmits its heat while passing through the casing to the steam within the tubes D In accordance with one feature of my invention the steam, after leaving the generator is subjected to a drying and a preliminary heating before being admitted to the heat transmitting device described. Such drying and preliminary heating of the steam is effected in a suitable casing E through which the steam is passed and preferably such preliminary heating is effected by the products of combustion which issue from the furnace C Said preliminary heating or drying casing is provided with a plurality of longitudinally arranged tubes E extending between and opening through heads 0 0 into end chambers e c of thecasing and the products of combustion enter through a passage 6* said end chambers e and pass thence through the tubes E the other end chamber 6 and outwardly therefrom through a flue E The steam enters said casing E through a pipe A and from thence issues through a pipe E to the heat transmitter of the super-heater. In its passage through the preliminary drying or heating apparatus E the steam is dried and to an extent heated by the waste products of combustion from the furnace. The discharge end of the pipe A is preferably made elon gated and opens into the side of the casing E so that any water carried by the steam is sprayed against the heated tubes or pipes E and is thereby vaporized. Any water collecting in the preliminary heater E is dis charged therefrom through a pipe E provided with a trap c, said pipe discharging into the steam space (Z of the heat transmitter.

The parts just described constitute an economizer by which is utilized the hot gases issuing from the furnace C to dry or presupcrheat the steam, and thus avoid waste of such hot gases and a corresponding waste of fuel. This arrangement of the economizer greatly increases the efiiciency of the superheater as a whole.

The superheating agent employed in the closed circuit of the superheating apparatus is one possessing a higher boiling point than that of the water from which the steam is generated, so that it is practicable to produce a suitably high temperature in the transmitter without producing an objectionable or unsafe pressure therein. In this manner the superheating device may be made of a suitably light structure, and at the same time be safely operated, as there is no danger, under the usual operating conditions of the apparatus of producing an unsafe or explosive pressure in the apparatus.

It is desirable in order to conserve the safety of the apparatus that means be pro vided for reducing the temperature in the furnace C in case the demand for the superheated steam suddenly ceases and prompt attention be not given to the apparatus to cut off the supply of heat to the superheating apparatus. For this purpose I propose to employ force derived from the variations of temperature of the superheating agent in the heat transmitter to regulate the sup ply of air to the furnace. This is effected in the present instance by means of a suitable thermostat which is subject to the heat of the superheating agent and is connected with the check-draft door 0 of the furnace in such manner that when the temperature of the superheating agent exceeds a certain maxim-um temperature at which the a-ppzu ratus is to operate, the thermostat has the effect of opening said check-draft door, thereby reducing the temperature of the furnace and with a corresponding reduct on of the temperature of the superheating agent.

The thermostat may be made of any suitable form, and the operative connections between the thermostat and the check-draft door anay be greatly varied. As herein shown, the thermostat consists of a tube I which extends into the transmitter and contains a rod 1 having greater co-efficient of expansibility than the tube 1. For instance, the tube I may be made of iron and the rod 1 of brass. The upper end of the rod I bears against the free end of the short arm 71 of a bell-crank lever pivoted at the upper end of the thermostat in a manner to swing the upper end of the longer arm 2' of said lever in a vertical plane. Said longer arm 2' of the bell-crank lever is connected by means of a suitable chain or cable I with an arm a rigid with the rock-shaft c which constitutes the bearing for said door. Said chain or cable is trained between the bellcrank lever and said arm 0 over a guide pulley The check-draft door 0 is preferably counterweighted, the shaft thereof being provided with a weighted arm 0*, which acts in opposition to the weight of the door, whereby the door may be opened with the exertion of little power. The door is normally closed during the usual operation of the apparatus. lVith this construction when the temperature of the superheating agent becomes excessive, the rod 1 expands and acts through the bell-crank lever and the cable or chain I to open the check-draft door and thereby decrease .or reduce the heat of the furnace in the manner before mentioned. By the use of this construction the device is automatically rendered safe. In case therefore, through careless use of the apparatus, or for other unforeseen cause, the fire of the furnace should not be promptly closed down upon cessation of the use of the superheated steam, the device described acts automatically to reduce the temperature of the furnace and thus prevent injury to the apparatus which might otherwise occur.

It is also desirable to provide means for rendering substantially constant the temperature of the superheated steam as it issues from the heat transmitter D and this is effected, in the present instance, through the medium of a suitably applied thermostatic device which is connected with and operates the draft-door of the furnace C. As herein shown, a thermostat consisting of a tube J and a bar J is located within the pipe D leading from the heat transmitter to the low pressure cylinder of the engine. The bar J bears upwardly against the end of the short arm of a bell-crank lever that is pivoted to the pipe D, and the longer arm 7' is connected through the medium of a cable or chain J 2 with an arm 0 of the rockshaft 0 constituting the bearing for the draft-door. Said chain or cable is trained over a suitably located guide pulley j. The adjustment of the parts is such that the draft-door remains normally open or partially open and closes by its gravity. The closing tendency of the door effects a tension on the cable or chain J and causes the short arm of the bell-crank lever to bear upon the upper end of the bar J In this construction the relation of the tube J and the bar J is reversed relatively to the thermostat before described. That is to say, the tube J is made of a metal having a greater co-efliciency of expansion than the bar J Vhen, therefore, the heat of the steam increases beyond a given or selected tempera ture, the tube J expands, thereby allowing the bar J to descend. Thereupon, the door 0 is closed by its gravity to a greater or less extent, depending upon the extent of fall of the thermostatic member J Then the temperature of the superheated steam decreases, the tube again contracts and acts, through the mechanism described, to open the draft door 0 to a greater or less extent and to correspondingly increase the temperature of the fire.

It is obvious that the structural details may be varied While retaining the advantages arising from the use of my improvements and I do not wish to be limited to the structural details shown except as hereinafter made the subject of specific claims.

I claim as my invention 1. An apparatus for superheating steam comprising, in combination with a steam generator and its furnace, a superheater arranged between the generator and the point of use of the steam through which the steam passes to its point of use, said superheater embracing apassage or passages in which circulates a liquid, through which liquid and the walls of the passage or passages the heat to superheat the steam is transmitted, a furnace, independent of the furnace which generates the steam, for heating said liquid, an economizer through which the gaseous products of combustion from the superheater furnace is discharged, and means whereby the steam to be superheated is passed through said economizer on its way to the superheater.

2. An apparatus for superheating steam comprising, in combination with a steam generator, a superheater arranged between the generator and the point of use of the steam, through which the steam passes to its point of use, said superheater embracing a passage or passages in which circulates a liquid, through which liquid and the walls of the passage or passages the heat to superheat the steam is transmitted, means for heating said heat transmitting liquid, and means controlled by the temperature of said liquid for varying the intensity of heat applied to heat the same.

3. An apparatus for generating and superheating steam, comprising a main steam generator and its furnace, a closed circuit containing a superheating agent, a heat transmitter through which the steam passes from the generator to the point of use, said heat transmitter forming a portion of the closed circuit and the superheating agent being separated from the steam therein by heat conducting walls, a furnace, separate from the generator furnace, for supplying heat to the heat transmitter, said furnace containing a part of said closed circuit and means controlled by variations of the temperature of the superheating agent in said closed circuit for controlling the amount of heat applied by said furnace to the said closed circuit.

4. An apparatus for superheating steam comprising, in combination with a steam generator, its furnace and an engine, a closed circuit adapted to contain a circulating superheating agent, a furnace, independent of the furnace for generating the steam, containing a part of said closed circuit and by which the superheating agent is heated, a heat transmitter through which the steam passes on its way from the generator to the engine, said heat transmitter forming a portion of the closed circuit, and the superheating agent being separated from the steam therein by heat conducting walls, an economizer which is heated by the products of combustion from said superheater, means for conducting the steam from the generator to the economizer, and means for conducting the steam from the economizer to the heat transmitter.

5. An apparatus for superheating steam comprising a closed circuit adapted to contain a circulating superheating agent, means for applying heat to said circuit, aheat transmitter through which the steam passes from the generator to its point of use, said heat transmitter forming a portion of said closed circuit and the superheating agent being separated from the steam therein by heat conducting walls, and means controlled by variations of the temperature of the superheating agent for varying the heat applied to said closed circuit.

6. An apparatus for superheating steam comprising a closed circuit adapted to contain a circulating superheating agent, means. for applying heat to said circuit, and a heat transmitter through which the steam passes from the generator to its point of use, said heat transmitter forming a portion of said closed circuit and the superheating agent being separated from the steam therein by In testimony, that I claim the foregoing heat conducting Walls means controlled by as my invention I aflix my signature in pres- 10 variations of the temperature of the superenoe of two witnesses, this 12th day of April heating agent for varying the temperature A. D. 1904.

" applied to said closed circuit, and means EUGENE F. OSBORNE.

controlled by the variations of the temperalVitnesses: ture of the superheated steam for also regu- V. L. HALL,

lating the heat applied to said closed circuit. GERTRUDE BRYCE. 

